1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to an image forming apparatus equipped with a paper feed mechanism for feeding paper.
2. Background Information
A thermal transfer printer is a known example of a conventional image forming apparatus equipped with a paper feed mechanism for feeding paper. Such paper feed mechanism of the thermal transfer printer generally has a paper feed roller for feeding paper, and a lifting member for pressing the paper against the paper feed roller. The lifting member is pivotably supported by side surfaces of a chassis, and is biased upward by a coil spring that is disposed underneath the lifting member.
As shown in FIG. 15, the lifting member 109 has two insertion holes 109a, an attaching part 109b, and a pressing part 109c. The lifting member 109 is pivotably supported by the side surfaces of the chassis at the two insertion holes 109a. 
As shown in FIG. 17, the attaching part 109b of the lifting member 109 is formed so as to engage a cam component 111a of a drive gear 111 with the biasing force of the compression coil spring 110. This compression coil spring 110 is disposed underneath and close to the pressing part 109c. Also, as shown in FIG. 16, the pressing part 109c of the lifting member 109 is disposed underneath a pressing plate 106a of the paper cassette 106.
The drive gear 111 is attached to the side surface of the chassis. A cam component 111a that engages the attaching part 109b of the lifting member 109 is provided to this drive gear 111. On this cam component 111a are formed a circular part 111b and a concave part 111c. 
The pressing plate 106a is provided in the paper cassette 106. This pressing plate 106a is formed to pivot around a fulcrum 106b. Also, as shown in FIG. 17, the pressing plate 106a is formed so as to press the paper 122 against the paper feed roller 102 when the pressing part 109c of the lifting member 109 is pushed up.
As seen in FIG. 16, the paper feed roller 102 is disposed above the pressing plate 106a of the paper cassette 106. Also, the paper feed roller 102 is designed so as to convey the paper in the paper feed direction (the direction of the arrow G in FIG. 17) when rotated.
Next, how paper is fed in a conventional thermal transfer printer will be described through reference to FIGS. 16, and 17. First, as shown in FIG. 16, the drive force from a motor causes the drive gear 111 to rotate in the direction of the arrow L in FIGS. 16 and 17. As a result, as shown in FIG. 16, the attaching part 109b of the lifting member 109 pivots from a state of being in contact with the circular part 111b of the drive gear 111 to a state of being in contact with the concave part 111c of the drive gear 111, as shown in FIG. 17.
Accordingly, as shown in FIG. 17, the lifting member 109 pivots around the insertion holes 109a in the direction of the arrow I shown in FIGS. 16 and 17, due to the biasing force of the compression coil spring 110. As a result, the pressing part 109c of the lifting member 109 causes the paper 122 supported by the pressing plate 106a of the paper cassette 106 to be pressed against the paper feed roller 102. Then, the drive force of the motor is transmitted to the paper feed roller 102, such that the paper 122 is conveyed in the direction of the arrow G.
However, with the conventional thermal transfer printer shown in FIGS. 15 to 17, because the lifting member 109 is pivotably supported by the side surfaces of the chassis, the length of the lifting member 109 is the same as the distance between the side surfaces of the chassis. Thus, the lifting member 109 is quite large, and cannot be made smaller.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved image forming apparatus that overcomes the problems of the related art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.